Women who used alprostadil (Femprox) cream had as much as 63% improvement in the primary outcome of satisfactory sexual encounters, as defined by responses to a validated sexuality questionnaire.

Younger women (<45) treated with the highest concentration of the medication had the greatest improvement compared with the placebo group.

Women who used the highest concentration of alprostadil cream had significant improvement in all primary and secondary endpoints compared with placebo, as reported here at the American Urological Association meeting.

"I think these results are exciting," Irwin Goldstein, MD, of San Diego Sexual Medicine in California, told MedPage Today. "Women have sexual problems, and we really haven't been addressing them. We haven't been giving them choices, like men have choices, and women need choices just like men do."

Topical alprostadil was generally well tolerated, and adverse events were consistent with drug's known effects, he added.

Alprostadil (Muse) has demonstrated efficacy in the treatment of erectile dysfunction in men. An injectable formulation is approved in the U.S. and a topical formulation has approval in Canada. The topical formulation's vehicle contains a proprietary skin-penetration enhancer that temporarily relaxes tight skin junctions to enable alprostadil delivery and penetration.

Effective tissue penetration by alprostadil results in vasodilation, smooth muscle relaxation, and increased blood flow. Men apply the cream to the head of the penis, whereas the higher dose developed for women is applied to the clitoris and distal anterior vaginal wall, considered the G spot.

"Everyone understands that when you have desire it leads to sexual activity, which is followed by blood flow to the genital tissue, causing an arousal and engorgement response," Goldstein said. "If a woman has issues with arousal, it's problematic. We understand that. That's what erectile dysfunction is in men. There's absolutely no reason not to think that there is a subgroup of women who are unhappy with their sex lives and who could improve their sex lives if they had an appropriate topical agent that's a little stronger than what is currently available."

The patients were randomized to placebo or one of three concentrations of alprostadil cream: 500, 700, or 900 µg. Each patient received 10 doses of randomized therapy, which was applied prior to sexual intercourse. Follow-up assessments occurred after three to five doses of therapy had been used.

The primary endpoint was defined as the proportion of women in each treatment group who answered "Yes" to Question 3 of the Female Sexual Encounter Profile: "Were you satisfied with your sexual arousal (excitement) during this sexual encounter?"

Overall, 33% of women allocated to placebo had improvement in satisfactory sexual encounters, compared with 46.3%, 43.5%, and 53.9% of women in the alprostadil groups (P=0.0400 to P=0.0002).

The study population consisted of 168 women ages 21 to 45 and 206 women ages 46 to 65, for a total of 374 in an intent-to-treat analysis. Evaluation of the primary endpoint by age group showed that 33% of placebo-treated patients had improvement regardless of age.

Age-stratified response rates differed across the alprostadil dose groups, but a higher proportion of women in each group had improvement compared with placebo. In the 500-µg arm, 49% of older women and 42% of younger women improved. In the 700-µg arm, 46% of younger women and 41% of older women improved.

The highest response rate occurred among younger women randomized to 900 µg of alprostadil, as they reported that 61% of sexual encounters were satisfactory (P<0.005 versus placebo). Older women had a 47% response rate.

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